An aircraft spacing system and other sensors onboard an ownship aircraft may be used to obtain positional information of a target aircraft to generate speed guidance to achieve and maintain a time and/or distance interval. For example, the speed guidance might be generated according to the requirements of Airborne Spacing-Flight Deck Interval Management (ASPA-FIM). ASPA-FIM may enable inter-aircraft spacing by, for example, adjusting the speed or path of the ownship aircraft. In one example, the aircraft spacing system may analyze positional information (e.g., range, altitude, direction, speed, etc.) to maintain the desired inter-aircraft spacing.